Ingredient for rubber, and rubber composition

Abstract

To provide an ingredient for a rubber containing an organosilicon compound yielding a rubber composition capable of realizing desired low fuel consumption performance and abrasion resistance performance while sustaining processability of a composition, hardness, and tensile property of a cured product thereof when added to a rubber composition.SOLUTION: An ingredient for a rubber contains an organosilicon compound expressed by the following formula (1). In the formula, R1 each independently represents a 1-8C alkyl group, and L represents a bivalent linking group. X represents -O-, and Z represents -N=R5 (R5 represents a 1-10C alkylidene group which may be substituted by a 6-20C aryl group, or heteroaryl group.), or X represents -NR2-, and R2 and Z by bonding mutually represent a ring structure together with a nitrogen atom bonded with these. m represents an integer of 1 to 3.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rubber compounding agent containing an organosilicon compound and a rubber composition.

Background Art

[0002] Silica-filled tires have excellent performance in automotive applications, especially in terms of abrasion resistance, rolling resistance, and wet grip performance. These performance improvements are closely related to the improvement of the fuel efficiency of tires. Therefore, in particular, in the industry of passenger car tires using solution-polymerized styrene-butadiene rubber (S-SBR), it has been actively studied recently.

[0003] Although silica-filled rubber compositions reduce the rolling resistance of tires and improve wet grip performance, they have high unvulcanized viscosity, require multi-stage kneading, etc., and have problems with workability. Therefore, in a rubber composition simply blended with an inorganic filler such as silica, problems such as insufficient dispersion of the filler and a significant decrease in fracture strength and abrasion resistance occur. Therefore, a sulfur-containing organosilicon compound is essential to improve the dispersibility of the inorganic filler in the rubber and to chemically bond the filler and the rubber matrix.

[0004] As the sulfur-containing organosilicon compound used as a rubber compounding agent, a compound containing an alkoxysilyl group and a polysulfide silyl group in the molecule, for example, bis-triethoxysilylpropyltetrasulfide, bis-triethoxysilylpropyldisulfide, etc. are known to be effective (see Patent Documents 1 to 4).

[0005] In addition, high load-bearing tires mounted on trucks, buses, etc. are required to have high fracture resistance so as to withstand use under severe conditions. Natural rubber is used as the rubber, but in such tires as well, the demand for improving fuel efficiency and abrasion resistance is increasing (Patent Document 5).

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-525230 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2004-18511 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2002-145890 [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2000-103795 [Patent Document 5] Japanese Unexamined Patent Application Publication No. 2019-131649 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] The present invention has been made in view of the above circumstances, and provides a rubber compounding agent containing an organosilicon compound that can achieve desired low fuel consumption performance and wear resistance while maintaining the processability of the composition, the hardness of the cured product, and the tensile properties when added to a rubber composition, a rubber composition containing this rubber compounding agent, and a tire formed from this rubber composition. [Means for Solving the Problems]

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that a predetermined organosilicon compound having a blocked isocyanate group and a hydrolyzable silyl group is suitable as a rubber compounding agent, and have found that a tire obtained from a rubber composition containing this rubber compounding agent can achieve desired low fuel consumption performance and wear resistance while maintaining hardness and tensile properties, thus completing the present invention.

[0009] That is, the present invention is 1. A rubber compounding agent containing (A) an organosilicon compound represented by the following formula (1), [Chemical Formula] (In the formula, R 1Each independently represents an alkyl group having 1 to 8 carbon atoms, L represents a divalent linking group. X represents -O-, and Z represents -N=R 5 (R 5 represents an alkylidene group having 1 to 10 carbon atoms which may be substituted with an aryl group or a heteroaryl group having 6 to 20 carbon atoms.). Or X represents -NR 2 -, R 2 and Z are bonded to each other and represent a ring structure selected from the following formulas formed together with the nitrogen atom to which they are bonded. m represents an integer of 1 to 3.). [Chemical formula] (In the formula, the wavy line represents the bonding position.). 2. The rubber compounding agent according to claim 1, wherein the component (A) is one or more selected from the organosilicon compounds represented by the following formula [Chemical formula] (In the formula, Me represents a methyl group and Et represents an ethyl group.). 3. The rubber compounding agent according to claim 2, wherein the component (A) is one or more selected from the organosilicon compounds represented by the following formula [Chemical formula] (In the formula, Me represents a methyl group and Et represents an ethyl group.). 4. Further, the rubber compounding agent according to any one of 1 to 3, which contains an organosilicon compound having one or more selected from a polysulfide group, a thioester group, and a mercapto group and an alkoxysilyl group 5. The rubber compounding agent according to claim 4, wherein the mixing ratio of the component (A) and the component (B) is (B) / (A) = 10 / 90 to 95 / 5 by mass 6. A rubber composition containing the rubber compounding agent according to any one of 1 to 5 7. Further (C) a diene rubber, and (D) a filler The rubber composition according to claim 6, which contains 8. The rubber composition contains components (A) to (D), the total blending amount of components (A) and (B) is 3 to 30 parts by mass with respect to 100 parts by mass of component (D), and the blending amount of component (D) is 5 to 200 parts by mass with respect to 100 parts by mass of component (C). The rubber composition according to claim 7, 9. A tire formed by molding the rubber composition according to any one of claims 6 to 8 is provided.

Effect of the Invention

[0010] The rubber composition blended with the compounding agent for rubber of the present invention is excellent in processability, and a tire formed using this rubber composition can satisfy the desired low fuel consumption tire characteristics and wear resistance while maintaining the hardness and tensile properties.

Mode for Carrying Out the Invention

[0011] Hereinafter, the present invention will be specifically described. 〔Compounding Agent for Rubber〕 The compounding agent for rubber of the present invention contains the following component (A).

[0012] [1] Component (A) Component (A) is a compound having a blocked isocyanate group and a hydrolyzable silyl group, and contains a blocked isocyanate group in which the isocyanate group is blocked by a blocking agent and a hydrolyzable silyl group such as a trimethoxysilyl group or a triethoxysilyl group. It is a compound.

[0013] Component (A) is preferably an organosilicon compound represented by the following formula (1).

Chemical formula

[0014] In formula (1), R 1 each independently represents an alkyl group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, L represents a divalent linking group, and X represents -O- or -NR 2represents -, Z represents a hydrogen atom or a monovalent organic group, and R 2 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a group capable of forming a ring structure by bonding with Z, and m represents an integer of 1 to 3, preferably 3.

[0015] R 1 The alkyl group having 1 to 8 carbon atoms of R may be linear, branched, or cyclic. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl groups, etc. Among these, R 1 is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group.

[0016] Specific examples of the divalent linking group of L include an alkylene group, -O-, -S-, -NR-, -C(=O)-, -C(=O)-O-, -NRCO-, -SO 2 -, and combinations thereof. Here, R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and a hydrogen atom is preferred. The alkyl group includes those having 1 to 4 carbon atoms among the alkyl groups exemplified above. Among these, as the divalent linking group of L, from the availability of raw materials in the production of organosilicon compounds, -(CH 2 ) n -(n is an integer of 1 to 10, preferably 1 to 6, more preferably 1 to 4), or a group in which one or more methylene units of this -(CH 2 ) n - are substituted with -O-, -S-, -NH-, -C(=O)-, and -C(=O)O- is preferred, and -(CH 2 ) 3 -(trimethylene group) is more preferred.

[0017] X in formula (1) is -O- or -NR 2-However, it is a group that forms part of the protecting group of the blocked isocyanate silane compound and is eliminated by heating, and is not particularly limited. -NR of X 2 -In, R 2 represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a group capable of forming a ring structure by bonding with Z. R 2 As the alkyl group having 1 to 8 carbon atoms of R, the same groups as those exemplified for the above R 1 can be mentioned. Among them, a linear or branched alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group or an ethyl group is more preferable. -NR 2 -In, R 2 When represents a group capable of forming a ring structure by bonding with Z, -NR 2 - preferably forms a heterocyclic structure with Z in formula (1). As the heteroatom in such a heterocyclic structure, it is preferable to contain 2 or more nitrogen atoms, and more preferably to contain 2 nitrogen atoms. As the heterocyclic structure, a 5-membered ring or 6-membered ring structure is preferable, and a 5-membered ring structure is more preferable.

[0018] Z in formula (1) is a hydrogen atom or a monovalent organic group, but it is a group that forms part of the protecting group of the blocked isocyanate silane compound and is eliminated by heating, and is not particularly limited. Specific examples of the monovalent organic group of Z may have a substituent and may contain an ether bond or an ester bond (however, excluding those containing O at the bonding terminal with an oxygen atom and generating an -O-O- bond), a monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydroxyl group (however, excluding the case where X is -O-), -N=R 5 (R 5 represents an alkylidene group having 1 to 10 carbon atoms which may be substituted by an aryl group or a heteroaryl group having 6 to 20 carbon atoms.) and the like can be mentioned. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include linear, branched, and cyclic groups, such as an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. Specific examples of the alkyl group include, in addition to the groups exemplified by R 1 , n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-icosyl groups, and the like. Specific examples of the aryl group include phenyl, naphthyl groups, and the like. Specific examples of the aralkyl group include benzyl, phenylethyl groups, and the like. In addition, at least a part of the hydrogen atoms of these groups may be substituted with other substituents. Examples of the other substituents include a carboxyl group, a hydroxyl group, an oxo group (=O), a thioxo group (=S), and the like. In the above formula -N=R 5 , examples of the alkylidene group having 1 to 10 carbon atoms, which may be substituted with an aryl group or a heteroaryl group having 6 to 20 carbon atoms for R 5 , include linear, branched, and cyclic groups. Specific examples thereof include methylidene, ethylidene, propylidene, propane-2-ylidene, butylidene, butane-2-ylidene, pentylidene, 4-methylpentane-2-ylidene, hexylidene, cyclohexylidene, heptylidene, octylidene, nonylidene, decylidene groups, and the like. Specific examples of the aryl group having 6 to 20 carbon atoms include the same groups as those exemplified for the above monovalent hydrocarbon group. Specific examples of the heteroaryl group having 6 to 20 carbon atoms include pyrrol-1-yl, 1H-pyrrol-2-yl, imidazol-1-yl, imidazol-2-yl, pyrazol-1-yl, pyrazol-3-yl, pyridin-2-yl, pyridin-3-yl groups, and the like. Specific examples of the substituted alkylidene group include phenylmethylene, diphenylmethylene groups, and the like.

[0019] (A) component is particularly preferably represented by the following formula (2).

[0020]

Chemical formula

[0021] R 2 and Z are the same as above. Among them, in particular, it is preferable that these are bonded to each other to form a ring structure together with the nitrogen atom to which R 2 and Z are bonded. Specific examples of the ring structure include an imidazole ring, a pyrazole ring, a 1,2,3-triazole ring, and a 1,2,4-triazole ring, with the pyrazole ring being more preferable. Note that the above ring structure may have a substituent such as an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a carboxyl group, a hydroxyl group, an ester group, an oxo group (=O), a halogen group such as chlorine or bromine, or a nitro group. Preferable ring structures include the following, but are not limited thereto.

[0022]

Chemical formula

[0023] Preferable specific examples of the (A) component include the following compounds, but are not limited thereto. The (A) component may be used alone or in combination of two or more.

[0024]

Chemical formula

[0025] (A) The manufacturing method of the component is not particularly limited, but a method of reacting a compound having an isocyanate group and a hydrolyzable silyl group in one molecule with a blocking agent is preferred. As the compound having an isocyanate group and a hydrolyzable silyl group in one molecule, for example, a compound represented by the following formula (3) can be used.

[0026]

Chemical formula

[0027] Specific examples of the compound represented by formula (3) include, for example, 1-isocyanatomethyltrimethoxysilane, 1-isocyanatomethyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 6-isocyanatohexyltrimethoxysilane, 6-isocyanatohexyltriethoxysilane, 8-isocyanatooctyltrimethoxysilane, 8-isocyanatooctyltriethoxysilane, and the like.

[0028] As the blocking agent, any conventionally known one can be used, and for example, those represented by the following formula (4) can be used.

Chemical formula

[0029] Specific examples of the compound represented by formula (4) include, for example, oxime compounds such as acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, cyclohexanone oxime, benzophenone oxime; phenol compounds such as phenol, para-tert-butylphenol, cresol; alcohol compounds such as n-butanol, 2-ethylhexanol, phenyl carbinol, methyl phenyl carbinol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, methoxymethanol; lactam compounds such as ε-caprolactam, γ-butyrolactam; pyrrole compounds such as pyrrole, 2H-pyrrole, 1-methylpyrrole, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, N-methylpyrrole; indole compounds such as indole, N-methylindole, 2-methylindole; pyrazole compounds such as pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, 4-nitro-3,5-dimethylpyrazole, 4-benzyl-3,5-dimethylpyrazole, methyl 5-methylpyrazole-3-carboxylate, 3-methyl-5-phenylpyrazole, 3,5-dimethylpyrazole-4-carboxyanilide; acid amide compounds such as acetanilide, acetanisidide, acetotoluidide, acrylamide, methacrylamide, acetic acid amide, stearic acid amide, benzamide; imide compounds such as succinimide, phthalimide, maleimide; amine compounds such as diphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, butylphenylamine; imidazole compounds such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, benzimidazole; triazole compounds such as 1,2,3-triazole, 1,2,4-triazole, 1,2,3-benzotriazole; piperidine compounds such as piperidine, N-methylpiperidine, 4-methylpiperidine;Urea compounds such as urea, thiourea, ethylene urea, ethylene thiourea, diphenyl urea, etc.; Carbamate ester compounds such as phenyl N-phenylcarbamate, etc.; Imine compounds such as ethyleneimine, propyleneimine, etc. are mentioned. In addition to the above compounds, active methylene compounds such as dimethyl malonate, diethyl malonate, diisopropyl malonate, ethyl acetoacetate, isopropyl acetoacetate, methyl acetoacetate, isopropyl acetoacetate, acetylacetone, etc.; Mercaptan compounds such as n-butyl mercaptan, tert-butyl mercaptan, n-hexyl mercaptan, tert-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methyl thiophenol, ethyl thiophenol, etc.; Sulfite compounds such as sodium bisulfite, potassium bisulfite, etc. can also be used. These can be used alone or in combination of two or more. Among these, as the blocking agent, lactam compounds, pyrazole compounds, pyrrole compounds, indole compounds, imidazole compounds, triazole compounds, piperidine compounds are preferred, and the following compounds are more preferred.

[0030] [Chemical formula]

[0031] The reaction of a compound having an isocyanate group and a hydrolyzable silyl group in one molecule with a blocking agent is preferably carried out in air or in an inert gas atmosphere such as nitrogen or argon, with respect to 1 mol of the compound having an isocyanate group and a hydrolyzable silyl group in one molecule, the blocking agent is used in a ratio of 0.1 to 5 mol, and more preferably 0.5 to 3 mol. The reaction temperature is not particularly limited, but 50 to 150 °C is preferred, and 60 to 120 °C is more preferred. The reaction time is also not particularly limited, but 1 to 10 hours is preferred, and 2 to 6 hours is more preferred.

[0032] [2] Component (B) In the compounding agent for rubber of the present invention, in addition to the component (A), an organosilicon compound having at least one selected from the group consisting of (B) a polysulfide group, a thioester group, and a mercapto group and an alkoxysilyl group can be used. As the component (B), there is no particular limitation as long as it is a compound having such a functional group. For example, any conventionally known silane coupling agent blended in a rubber composition for applications such as tires can be used.

[0033] Specific examples of the silane coupling agent include polysulfide-based organosilicon compounds such as bis-(3-bistriethoxysilylpropyl)-tetrasulfide and bis-(3-bistriethoxysilylpropyl)-disulfide; mercapto-based organosilicon compounds such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; and thioester-based organosilicon compounds such as 3-octanoylthiopropyltriethoxysilane and 3-propionylthiopropyltrimethoxysilane. In addition, reaction products of the above-mentioned organosilicon compound having a sulfur atom and an alcohol containing a polyether group, hydrolysis condensates of these organosilicon compounds, and co-hydrolysis condensates of these organosilicon compounds and other organosilicon compounds having an alkoxysilyl group can also be used. The component (B) may be used alone or in combination of two or more.

[0034] In the compounding agent for rubber of the present invention, when the component (B) is blended, the blending ratio of the component (A) and the component (B) is not particularly limited, but the mass ratio (B) / (A) is preferably 10 / 90 to 95 / 5, more preferably 50 / 50 to 95 / 5.

[0035] At least one kind of powder may be added to the compounding agent for rubber of the present invention. Specific examples of the powder include carbon black, talc, calcium carbonate, stearic acid, silica, aluminum hydroxide, alumina, magnesium hydroxide, and the like. Among these, from the viewpoint of reinforcement, silica and aluminum hydroxide are preferred, and silica is more preferred.

[0036] When blending the powder, considering the handleability of the rubber compounding agent, transportation cost, etc., the blending amount is based on the mass ratio ((X) / (Y)) of the total amount (X) of the above component (A) or components (A) and (B) to the total amount of powder (Y), and 70 / 30 to 5 / 95 is preferred, and 60 / 40 to 10 / 90 is more preferred.

[0037] In addition, the rubber compounding agent of the present invention may be mixed with organic polymers such as fatty acids, fatty acid salts, polyethylene, polypropylene, polyoxyalkylene, polyester, polyurethane, polystyrene, polybutadiene, polyisoprene, natural rubber, styrene-butadiene copolymer, etc. and rubber, and may also be those blended with various additives usually used for tires, such as vulcanizing agents, crosslinking agents, vulcanization accelerators, crosslinking accelerators, various oils, antioxidants, fillers, plasticizers, etc., and other general rubber uses. Moreover, as its form, it may be liquid, solid, further diluted with an organic solvent, or emulsified.

[0038] [Rubber composition] The rubber composition of the present invention contains the above-described rubber compounding agent. Preferably, it contains the above-described component (A) or components (A) and (B), (C) diene rubber, and (D) filler. Considering the physical properties of the resulting rubber, the balance between the degree of the effects exerted, and economy, etc., the blending amount of component (A) or components (A) and (B) in the rubber composition of the present invention is preferably 3 to 30 parts by mass, and more preferably 5 to 20 parts by mass, based on 100 parts by mass of component (D) described in detail later.

[0039] [3] Component (C) As the diene rubber of component (C), any rubber generally used in various rubber compositions can be used conventionally. Specific examples thereof include various isoprene rubbers (IR) such as natural rubber, various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), and diene rubbers such as acrylonitrile-butadiene copolymer rubber (NBR). These may be used alone or in combination of two or more.

[0040] In particular, component (C) preferably contains natural rubber. From the viewpoint that sufficient fracture resistance characteristics can be obtained even when used as a tire for high-load vehicles, the content of natural rubber in component (C) is preferably 50% by mass or more, more preferably 70 to 100% by mass. As the natural rubber, those generally used in the tire industry such as RSS#3, SIR20, and TSR20 can be used. Also, modified natural rubbers such as epoxidized natural rubber, hydrogenated natural rubber, grafted natural rubber, and deproteinized natural rubber can be used.

[0041] In addition to the diene rubber, non-diene rubbers such as butyl rubber (IIR) and ethylene-propylene copolymer rubber (EPR, EPDM) may be used in combination.

[0042] [4] Component (D) Examples of the filler for component (D) include fillers generally used in the tire industry such as silica, carbon black, aluminum hydroxide, alumina (aluminum oxide), calcium carbonate, talc, and clay. These may be used alone or in combination of two or more. Among these, it is preferable to contain silica and carbon black, and it is more preferable to contain only silica and carbon black.

[0043] Examples of the carbon black include those generally used in the tire industry such as GPF, FEF, HAF, ISAF, and SAF. Examples of silica include those commonly used in the tire industry, such as silica prepared by the dry method (anhydrous silica) and silica prepared by the wet method (hydrous silica). Among them, silica prepared by the wet method is preferred because it has a large number of silanol groups. In particular, the silica preferably has a nitrogen adsorption specific surface area (N 2 SA) of 70 m 2 / g or more, more preferably 100 m 2 / g or more. The upper limit of N 2 SA is not particularly limited, but from the viewpoint of ease of handling, etc., it is preferably 500 m 2 / g or less, more preferably 400 m 2 / g or less.

[0044] When the component (D) is blended into the rubber composition of the present invention, the blending amount is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and even more preferably 20 to 130 parts by mass with respect to 100 parts by mass of the component (C) from the viewpoints of dispersibility, low fuel consumption property, and moldability. When the rubber compounding agent contains a powder, the above blending amount is the total amount with the powder.

[0045] In addition to the components (A) to (D) described above, the rubber composition of the present invention can be blended with various additives generally blended for tires, such as sulfur, crosslinking agents, vulcanization accelerators, crosslinking accelerators, various oils, antioxidants, plasticizers, various resins, waxes, zinc oxide, and other additives generally blended for rubbers. The blending amounts of these additives can be the conventional general blending amounts as long as they do not contravene the object of the present invention.

[0046] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. These may be used alone or in combination of two or more. For example, products available from Tsuruimi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0047] When sulfur is blended, the blending amount is preferably 0.1 part by mass or more and 5.0 parts by mass or less, more preferably 0.3 part by mass or more and 2.0 parts by mass or less, and still more preferably 0.5 part by mass or more and 1.5 parts by mass or less with respect to 100 parts by mass of the component (C). When it is within the above range, the balance between tensile properties and abrasion resistance is good.

[0048] [Rubber product (tire)] The rubber composition of the present invention comprises the above-described components (A) to (D) and other components into a composition by a general method, and by vulcanizing or crosslinking this, it can be used, for example, in the production of rubber products such as tires. In particular, when producing a tire, it is preferable that the rubber composition of the present invention is used for the tread. The tire obtained by using the rubber composition of the present invention can achieve desired low fuel consumption because, in addition to reducing rolling resistance, its abrasion resistance is improved. Note that the structure of the tire can be a conventionally known structure, and its manufacturing method may also adopt a conventionally known manufacturing method. Further, in the case of a pneumatic tire, as the gas filled in the tire, usually, in addition to air and air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used.

Examples

[0049] Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to these examples. In the following examples, Me represents a methyl group and Et represents an ethyl group.

[0050] [1] Synthesis of organosilicon compound [Synthesis Example 1-1] After charging 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) into a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, 68 g (1.0 mol) of imidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Then, by performing a filtration step, an organosilicon compound (A-1) represented by the following formula was obtained.

[0051]

Chem.

[0052] [Synthesis Example 1-2] 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) was placed in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer. Then, 82 g (1.0 mol) of 2-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-2) represented by the following formula was obtained.

[0053]

Chem.

[0054] [Synthesis Example 1-3] 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) was placed in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer. Then, 222 g (1.0 mol) of 2-undecylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-3) represented by the following formula was obtained.

[0055]

Chem.

[0056] [Synthesis Example 1-4] A 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 96 g (1.0 mol) of 3,5-dimethylpyrazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80 °C, and the mixture was aged at 80 °C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-4) represented by the following formula was obtained.

[0057] [Chemical formula]

[0058] [Synthesis Example 1-5] A 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 119 g (1.0 mol) of 1,2,3-benzotriazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80 °C, and the mixture was aged at 80 °C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-5) represented by the following formula was obtained.

[0059] [Chemical formula]

[0060] [Synthesis Example 1-6] A 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer was charged with 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 69 g (1.0 mol) of 1,2,4-triazole (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80 °C, and the mixture was aged at 80 °C for 4 hours. Thereafter, by performing a filtration step, an organosilicon compound (A-6) represented by the following formula was obtained.

[0061] [Chemical formula]

[0062] [Synthesis Example 1-7] After placing 247 g (1.0 mol) of 3-isocyanatopropyltriethoxysilane (KBE9007N, manufactured by Shin-Etsu Chemical Co., Ltd.) in a 500 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer, 113 g (1.0 mol) of ε-caprolactam (manufactured by Tokyo Chemical Industry Co., Ltd.) was added at 80°C, and aging was carried out at 80°C for 4 hours. Then, by performing a filtration step, an organosilicon compound (A-7) represented by the following formula was obtained.

[0063] [Chemical Formula]

[0064] [Synthesis Example 1-8] 539 g (1.0 mol) of bis(triethoxysilylpropyl)tetrasulfide (KBE-846, manufactured by Shin-Etsu Chemical Co., Ltd.), 222 g (0.8 mol) of octyltriethoxysilane (KBE-3083, manufactured by Shin-Etsu Chemical Co., Ltd.), and 200 g of ethanol were placed in a 1 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer. Then, 25.2 g (1.4 mol of water) of 0.5N hydrochloric acid was added dropwise at room temperature. Next, the mixture was stirred at 80°C for 10 hours. Then, 3.0 g of propylene oxide was added dropwise, and the mixture was stirred at 80°C for 2 hours. Furthermore, by concentration under reduced pressure and filtration, an organopolysiloxane (B-2) in the form of a brown transparent liquid represented by the following average composition formula with a kinematic viscosity of 80 mm 2 / s was obtained. (-C 3 H 6 -S 4 -C 3 H 6 -) 0.36 (-C 8 H 17 ) 0.28 (-OC 2 H 5 ) 2.00 SiO 0.50 ···(B-2)

[0065] [2] Preparation of Rubber Compounding Agent [Examples 1-1 to 1-9] Using a 200 mL separable flask equipped with a stirrer, each component was mixed in the compounding amounts (parts by mass) shown in Table 1 to obtain a rubber compounding agent.

[0066]

Table 1

[0067] [3] Preparation of Rubber Composition [Examples 2-1 to 2-9, Comparative Examples 2-1, 2-2] Using a 4 L internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.), the natural rubber described in Tables 2 and 3 was kneaded for 60 seconds. Next, the natural rubber, carbon black, silica, rubber compounding agent obtained in Examples 1-1 to 1-9, stearic acid, anti-aging agent, resin, and wax described in Tables 2 and 3 were added, the internal temperature was raised to 150 °C, and then discharged. Thereafter, it was stretched using a roll. The obtained rubber composition was kneaded again using an internal mixer (MIXTRON, manufactured by Kobe Steel, Ltd.) until the internal temperature reached 145 °C, discharged, and then stretched using a roll. Zinc oxide, vulcanization accelerator, and sulfur described in Tables 2 and 3 were added thereto and kneaded to obtain a rubber composition.

[0068] Natural Rubber: RSS#3 Carbon Black: Seast 9H (manufactured by Tokai Carbon Co., Ltd.) Silica: Nipsil AQ (manufactured by Tosoh Silica Corporation) Stearic Acid: Industrial Stearic Acid (manufactured by Kao Corporation) Anti-aging Agent: No Crack 6C (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) Resin: T-REZ RA-100 (manufactured by ENEOS Corporation) Wax: Oz Ace 0355 (manufactured by Nippon Seiro Co., Ltd.) Zinc Oxide: Zinc Oxide No. 3 (manufactured by Mitsui Mining & Smelting Co., Ltd.) Vulcanization accelerator (a): Nocceler DM-P (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanization accelerator (b): Nocceler CZ-G (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Sulfur: 5% oil-treated sulfur (manufactured by Hosoi Chemical Industry Co., Ltd.)

[0069] For the rubber compositions obtained in Examples 2-1 to 2-9 and Comparative Examples 2-1 and 2-2, the unvulcanized physical properties and vulcanized physical properties were measured by the following methods. The results are also shown in Tables 2 and 3. Regarding the vulcanized physical properties, the obtained rubber composition was press-molded (145 °C, 30 minutes) to produce a vulcanized rubber sheet (thickness 2 mm).

[0070] [Unvulcanized physical properties] (1) Mooney viscosity In accordance with JIS K 6300-1:2013, measured at a temperature of 130 °C with a 1-minute afterheat and a 4-minute measurement, and expressed as an index with Comparative Example 2-1 as 100. The smaller the index value, the lower the Mooney viscosity and the better the processability. [Vulcanized physical properties] (2) Hardness The durometer (type A) hardness was measured in accordance with JIS K 6253-3:2012 and expressed as an index with Comparative Example 2-1 as 100. (3) Tensile properties A JIS No. 3 dumbbell-shaped test piece was punched out, and a tensile test was carried out at a tensile speed of 500 mm / min in accordance with JIS K6251, and the 300% modulus (M 300 ) [MPa] was measured at room temperature. The obtained results were expressed as an index with Comparative Example 2-1 as 100. The larger the index value, the higher the modulus and the better the tensile properties. (4) Dynamic viscoelasticity (strain dispersion) Using a viscoelasticity measuring device (manufactured by Metravib), the storage modulus E’(0.5%) at a strain of 0.5% and the storage modulus E’(3.0%) at a strain of 3.0% were measured under the conditions of a temperature of 25°C and a frequency of 55 Hz, and the value of [E’(0.5%) - E’(3.0%)] was calculated. The test piece used was a sheet with a thickness of 0.2 cm and a width of 0.5 cm, and the initial load was set to 1 N with a distance between the used clamps of 2 cm. The value of [E’(0.5%) - E’(3.0%)] was expressed as an index with Comparative Example 2-1 taken as 100. The smaller the index value, the better the dispersibility of silica. (5) Dynamic viscoelasticity (temperature dispersion) Using a viscoelasticity measuring device (manufactured by Metravib), the measurement was carried out under the conditions of a dynamic tensile strain of 1% and a frequency of 55 Hz. The test piece used was a sheet with a thickness of 0.2 cm and a width of 0.5 cm, and the initial load was set to 1 N with a distance between the used clamps of 2 cm. The value of tanδ(60°C) was expressed as an index with Comparative Example 2-1 taken as 100. The smaller the index value of tanδ(60°C), the better the rolling resistance. (6) Abrasion resistance Using an FPS tester (manufactured by Ueshima Seisakusho Co., Ltd.), the test was conducted under the conditions of a sample speed of 200 m / min, a load of 20 N, a road surface temperature of 30°C, a slip ratio of 5% and a slip ratio of 20%. The obtained results were expressed as an index with Comparative Example 2-1 taken as 100. The larger the index value, the less the wear amount and the better the abrasion resistance.

[0071]

Table 2

[0072]

Table 3

[0073] As shown in Tables 2 and 3, the vulcanizates of the rubber compositions of Examples 2-1 to 2-9 have low dynamic viscoelasticity, that is, small hysteresis loss and low heat generation, while maintaining the hardness and tensile properties, as compared with the vulcanizates of the rubber compositions of Comparative Examples 2-1 and 2-2, and it can be seen that they are excellent in abrasion resistance.

Claims

1. (A) A compounding agent for rubber containing an organosilicon compound represented by the following formula (1): 【Chemistry 1】 (In the formula, R 1 each independently represents an alkyl group having 1 to 8 carbon atoms, L represents a divalent linking group, X represents -O-, and Z represents -N=R 5 (R 5 represents an alkylidene group having 1 to 10 carbon atoms which may be substituted with an aryl group or heteroaryl group having 6 to 20 carbon atoms; 2 - represents R 2 and Z are bonded to each other to form a ring structure selected from the following formulae, together with the nitrogen atom to which they are bonded; and m is an integer of 1 to 3. 【Chemistry 2】 (In the formula, the wavy line represents the bond.)

2. 2. The rubber compounding agent according to claim 1, wherein the component (A) is one or more organosilicon compounds selected from the group consisting of organosilicon compounds represented by the following formulas: 【Chemistry 3】 (In the formula, Me represents a methyl group, and Et represents an ethyl group.)

3. 3. The rubber compounding agent according to claim 2, wherein said component (A) is one or more organosilicon compounds selected from the group consisting of organosilicon compounds represented by the following formulas: 【Chemistry 4】 (In the formula, Me represents a methyl group, and Et represents an ethyl group.)

4. The compounding agent for rubber according to any one of claims 1 to 3, further comprising (B) an organosilicon compound having an alkoxysilyl group and at least one group selected from the group consisting of a polysulfide group, a thioester group and a mercapto group.

5. 5. The rubber compounding agent according to claim 4, wherein the compounding ratio of the components (A) and (B) is, by mass, (B) / (A)=10 / 90 to 95 / 5.

6. A rubber composition comprising the compounding agent for rubber according to any one of claims 1 to 5.

7. moreover, (C) a diene rubber, and (D) Filler The rubber composition according to claim 6, which comprises

8. The rubber composition according to claim 7, wherein the rubber composition comprises components (A) to (D), the total amount of components (A) and (B) is 3 to 30 parts by mass per 100 parts by mass of component (D), and the amount of component (D) is 5 to 200 parts by mass per 100 parts by mass of component (C).

9. A tire formed by molding the rubber composition according to any one of claims 6 to 8.

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